Identification of polymorphs of sp3 bonded carbon and boron nitride using core-level absorption spectroscopy

The 1s core-level absorption spectra of the sp3 bonded carbon (cubic and hexagonal polymorphs) and boron nitrides (zincblende and wurtzite polymorphs) were calculated using an ab initio pseudopotential plane wave method including the core-hole effects. A comprehensive comparison with the available experimental data shows that there exist characteristic features that can be used to spectroscopically identify the different polymorphs. The anisotropic characters of K-edge absorption spectra in hexagonal diamond and wurtzite boron nitride can provide additional phase specific signatures. The application of the spectroscopic fingerprinting method in the experimental identification of these metastable sp3 bonded phases is discussed.